Correct answer. Both of them are prototherians and are egg-laying mammals. Mammals are in general viviparous, i.e., give direct birth to their young ones but there is one sub-class prototheria in which the mammals lay eggs, i.e., oviparous. These are most primitive mammals confined to Australia. Tachyglossus, Zaglossus, Ornithorhyncus are main examples of this sub-class.

Correct answer. Small / micro bats use echo-location for their food, prey and survival. Flying mammals belong to order Chiroptera, where forelimbs are modified into wings to help them fly. Flying mammals mainly include bats belonging to two sub-orders-frugivorous, large bats (Pteropus, Cynopterus) are placed in sub-order Megachiroptera while Microchiroptera include insectivorous little bats (Myotis, Rhinolophus, Vespertilio and Desmodus). The microbats use echo-location to detect their surroundings, prey, path etc.

Correct answer This blue-coloured pigment is found in arthropods and molluscs.

Correct answer. All of these belong to order Cetacea. Cetacea and Sirenia are two orders of class mammalia.They are mosinus delphistly marine, large fish like mammals adapted to life in water. Cetaceans are predominantly carnivorous animals, e.g., Balaenoptera musculus(blue whale), Delphinus delphis(dolphin), Phocaena(porpoise). Sirenians on the other hand are herbivores, e.g., Manatee(Trichechus) and Dugong (Dugong dugon).

Correct. Crocodile has four chambered heart. Four chambered heart is the characteristic feature of birds and mammals.There are two auricles and two ventricles, blood passes through heart twice thus making the type of circulation as double circulation. But besides birds and mammals,during the course of evolution,crocodiles have also acquired four-chambered heart although it is a reptile which posses three-chambered heart.

Correct answer. Opossum has the shortest gestation period of 12 to 14 days only. In mammals the gestation duration varies from few days to many months in different orders depending upon their development. Order Marsupialia has the shortest gestation periods as the young ones are born very immature and complete development in the marsupium only.The gestation period is shortest for any mammal in case of opossum,which is only 12 to 14 days only. The new born takes 50 to 60 days in marsupium to develop fully and come out of it.

Correct. Ctenophorans use ciliary comb plates for locomotion. Ctenophora is a phylum of animals that live in marine waters worldwide. Their most distinctive feature is the "e;e;combs"e;e;, groups of cilia they use for swimming, and they are the largest animals that swim by means of cilia.

Correct answer. Thermoacidophiles favour hot and acidic environments. Archaebacteria: There are three major known groups of Archaebacteria: methanogens, halophiles and thermophiles. The methanogens are anaerobic bacteria that produce methane. They are found in sewage treatment plants, bogs and the intestinal tracts of ruminants. Ancient methanogens are the source of natural gas. Halophiles are bacteria that thrive in high salt concentrations such as those found in salt lakes or pools of sea water. Thermoacidophiles are the heat-loving bacteria found near hydrothermal vents and hot springs.

Correct answer. It can not  regulate its body temperature. Its body temperature falls while inactive. Mammals are warm blooded animals, i.e., they can regulate their body temperature, have constant body temperature, without being influenced by outer environment. But some animals do not fall neatly into the categories of being warm or cold-blooded. Bats, for example, are mammals who cannot maintain a constant body temperature and cool off when they are not active. Echidnas maintain a range of body temperatures which usually lies between 77 and 98.6 degrees Fahrenheit and have difficulty cooling down. Mole Rats are another group of mammals who are unable to regulate their body temperature but they go deep down the ground to avoid temperature extremes.

Correct answer, all are homeothermic animals. Vertebrates show lot of variations as we move up in their hierarchy, i.e., moving from fishes to mammals.Their habitat changes from water to land to air, similarly they exhibit changes in their nutrition, survival traits, reproduction etc.While combating various types of environments vertebrates also learnt to regulate their own body temperatures to face weather extremes. Some of them could not do so are now called cold-blooded animals(body temp. varies with environment) e.g. fish, amphibians, reptiles. While those who could regulate are called warm-blooded animals e.g. birds,mammals. Humans, dogs, cats, bears, lions, most types of birds, and horses are some examples of a warm blooded animal. These animals have the ability to maintain their body's temperature, no matter what type of environment they are in. They are not dependent on the environment to heat or cool their bodies, in other words.

Correct answer. Both are freshwater sponges. Phylum porifera consists of mainly marine animals living in deep seas but few species are also found in freshwaters e.g. spongilla. Marine animals/sponges belong to classes Calcarea and Hexactinellida while fresh water sponges are placed in class Demospongiae.

Correct answer. All of these are classes of phylum Porifera. Calcarea, Hexactinellida and Demospongiae are classes of phylum Porifera. Cnidaria is a separate phylum, Turbellaria is a class of phylum Platyhelminthes while Hirudinaria is Indian common leech.

Correct answer. It has a body temperature ranging from 77 - 98.6 degrees and this keeps changing with seasons. Warm-blooded creatures, like mammals and birds, try to keep the inside of their bodies at a constant temperature. They do this by generating their own heat when they are in a cooler environment, and by cooling themselves when they are in a hotter environment but keep body temperature fixed or same throughout the year e.g. 37 degrees celsius in humans. However, Echidnas maintain a range of body temperatures which usually lies between 77 and 98.6 degrees Fahrenheit and have difficulty cooling down.There are some mammals who are not able to tolerate extreme conditions so they show different adaptations e.g. hibernation, to adjust in such conditions without compromising on their thermoregulation.

Correct answer. Doliolum, Pyrosoma and Amphioxus all are chordates. Chordates are the animals, which possess a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail for at least some period of their life. The phylum chordataU includes the subphyla Vertebrata, including mammals, fish, amphibians, reptiles, birds; Urochordata/ Tunicata, (including Herdmania- sea squirts, Doliolum, Pyrosoma)and Cephalochordata, comprising the lancelets(Branchiostoma). The phylum Hemichordata including the acorn worms was earlier considered fourth chordate subphylum, but it now is usually treated as a separate phylum. It, along with the phylum Echinodermata, including starfish, sea urchins, and sea cucumbers are nearest relatives of chordates.

Correct answer. Peripatus belongs to Onychophora Peripatus is an (onychophore) invertebrate, which looks like a caterpillar. However, on closer examination the external appearance is more like an annelid (earth) worm. In fact, it is also called a 'velvet worm'. The head is continuous with the body. The eyes probably distinguish only light and dark. The outer cuticle is thin and flexible, with no external segmentation (divisions). Peripatus is commonly called velvet worm.Velvet worms share a number of characteristics with both phylum Annelida (segmented worms) and phylum Arthropoda. Some authors place onychophorans in a subphylum within the phylum Arthropoda, but others regard the Onychophora as a separate phylum.